1. Field of Invention
The invention relates to a sheet feeding device for an image forming apparatus, and specifically relates to a sheet feeding device being capable of preventing overlapped feeding.
2. Description of Related Art
A sheet feeding device for feeding a sheet of printing medium, such as paper, into the inside of electronic apparatuses, is provided for electronic apparatuses having an image forming apparatus, such as a printer, a copier, or a facsimile device. In the feeding device, there has been known a feeding device provided with a frictional separating device for separating sheets of paper or the like, one at a time to feed the paper from a paper supplying roller. A separating piece then separates the sheets of paper one at a time through contact with the supplying roller.
The paper, which is fed one at a time by the frictional separating device, is fed in the paper transferring direction by the rotation of the supplying roller with a fixed pressure received from the sheet supplying roller and the separation piece. The paper is transferred to the inside of the electronic apparatus by the transferring roller provided in the lower stream side of the paper transferring direction. In the sheet feeding device of this structure, because of the back tension generated between the paper supplying roller and the transferring roller in supplying paper, paper is fed to the transferring roller side more than a predetermined transferring amount at the moment that the rear end of the paper is released from being held by the supplying roller and the separation piece. This back tension causes deterioration of the accuracy of transferring paper.
Therefore, the above-described deterioration of the accuracy of transferring paper is prevented by decreasing the pressure generated between the paper supplying roller and the separation piece, thereby decreasing the back tension between the paper supplying roller and the transferring roller.
However, by decreasing the pressure generated between the paper supplying roller and the separation piece, a great amount of paper may easily enter between the paper supplying roller and the separation piece and cause overlapped feeding, wherein a plurality of papers are unnecessarily transferred into the inside of the electronic apparatuses with the paper that is to be fed.